Granzyme B cleaves Tenascin-C to release its C-terminal domain in rheumatoid arthritis

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Abstract

Rheumatoid arthritis (RA) is one of the most common autoimmune disorders and is characterized by exacerbated joint inflammation that can lead to tissue remodeling and autoantigen generation. Despite the well-documented accumulation of the serine protease Granzyme B (GzmB) in the biospecimens of patients with RA, little is understood pertaining to its role in pathobiology. In the present study Tenascin-C (TN-C), a large extracellular matrix glycoprotein and an endogenous trigger of inflammation, was identified as a substrate for GzmB in RA. GzmB cleaves TN-C in vitro to generate three fragments: a 130 kDa fragment that remains anchored to the matrix, and two 70 and 30 kDa fragments that are released and solubilized. Mass spectrometry results seem to indicate that the 30 kDa fragment generated by GzmB most likely contains TN-C pro-inflammatory C-terminal fibrinogen-like domain. Soluble levels of GzmB and TN-C are also significantly elevated in the synovial fluids of RA patients compared to healthy controls, with two 70 kDa and 30 kDa soluble TN-C fragments detectable in the synovial fluids of RA patients. The molecular weights of these fragments coincide with those generated by GzmB in vitro, suggesting that GzmB also cleaves TN-C in RA patients. Granzyme K (GzmK), another member of the granzyme family, also cleaves TN-C in vitro. However, unlike GzmB, the molecular weights of TN-C fragments generated by GzmK in vitro do not correspond to fragments identified in patients. Altogether, our data supports the contribution of Granzyme B, but not Granzyme K, to RA through the cleavage of Tenascin-C.

Authors

Alexandre Aubert, Amy Liu, Martin Kao, Jenna Goeres, Katlyn C. Richardson, Lorenz Nierves, Karen Jung, Layla Nabai, Hongyan Zhao, Gertraud Orend, Roman Krawetz, Philipp F. Lange, Alastair Younger, Jonathan Chan, David J. Granville

Inhibiting Triggering Receptor Expressed on Myeloid Cells-1 signaling to ameliorate skin fibrosis

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Abstract

Systemic sclerosis (SSc) is characterized by immune system failure, vascular insult, autoimmunity, and tissue fibrosis. Transforming growth factor-beta (TGF-β) is a crucial mediator of persistent myofibroblast activation and aberrant extracellular matrix production in SSc. The factors responsible for this are unknown. By amplifying pattern recognition receptor signaling, Triggering Receptor Expressed on Myeloid Cells 1 (TREM-1) is implicated in multiple inflammatory conditions. In this study, we used novel ligand-independent TREM-1 inhibitors in order to investigate the pathogenic role of TREM-1 in SSc, using preclinical models of fibrosis, and explanted SSc skin fibroblasts. Selective pharmacological TREM-1 blockade prevented and reversed skin fibrosis induced by bleomycin in mice and mitigated constitutive collagen synthesis and myofibroblast features in SSc fibroblasts in vitro. Our results implicate aberrantly activated TREM-1 signaling in SSc pathogenesis, identify a unique approach to TREM-1 blockade, and suggest a potential therapeutic benefit for TREM-1 inhibition.

Authors

Swarna Bale, Priyanka Verma, Bharath Yalavarthi, Matija Bajželj, Syed A.M. Hasan, Jenna N. Silverman, Katherine Broderick, Kris A. Shah, Timothy Hamill, Dinesh Khanna, Alexander B. Sigalov, Swati Bhattacharyya, John Varga

NK cell subsets define sustained remission in rheumatoid arthritis

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Abstract

Rheumatoid Arthritis (RA) is an immune-mediated, chronic inflammatory condition. With modern therapeutics and evidence-based management strategies, achieving sustained remission is increasingly common. To prevent complications associated with prolonged use of immunosuppressants, drug tapering or withdrawal is recommended. However, due to the lack of tools that define immunological remission, disease flares are frequent, highlighting the need for a more precision medicine-based approach. Utilising high dimensional phenotyping platforms, we set out to define peripheral blood immunological signatures of sustained remission in RA. We identified that CD8+CD57+KIR2DL1+ NK cells are associated with sustained remission. Functional studies uncovered an NK cell subset characterized by normal degranulation responses and reduced pro-inflammatory cytokine expression, which was elevated in sustained remission. Furthermore, flow cytometric analysis of NK cells from synovial fluid combined with interrogation of a publicly available single cell RNA-seq dataset of synovial tissue from active RA identified a deficiency of the phenotypic characteristics associated with this NK cell remission signature. In summary, we have uncovered a novel RA remission signature associated with compositional changes in NK cell phenotype and function that has implications for understanding the impact of sustained remission on host immunity and distinct features which may define operational tolerance in RA.

Authors

Carl Coyle, Margaret Ma, Yann Abraham, Christopher B. Mahony, Kathryn Steel, Catherine Simpson, Nadia Guerra, Adam P. Croft, Stephen Rapecki, Andrew Cope, Rowann Bowcutt, Esperanza Perucha

Giantin mediates Golgi localization of Gal3-O-sulfotransferases and affects salivary mucin sulfation in Sjögren’s disease patients

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Abstract

Sjögren’s disease is a chronic autoimmune disease characterized by symptoms of oral and ocular dryness and extra-glandular manifestations. Mouth dryness is not only due to reduced saliva volume but also to alterations in the quality of salivary mucins in these patients. Mucins play a leading role in mucosa hydration and protection, where sulfated and sialylated oligosaccharides retain water molecules at the epithelial surface. The correct localization of glycosyltransferases and sulfotransferases within the Golgi apparatus determines adequate O-glycosylation and sulfation of mucins, which depends on specific golgins that tether enzyme-bearing vesicles. Here, we show that a golgin called Giantin is mislocalized in salivary glands from patients with Sjögren’s disease and forms protein complexes with Gal3-O-sulfotransferases (Gal3STs), which change their localization in Giantin knockout and knockdown cells. Our results suggest that Giantin could tether Gal3ST-bearing vesicles and that its altered localization could affect Gal3ST activity, explaining the decreased sulfation of MUC5B observed in salivary glands from patients with Sjögren’s disease.

Authors

Matilde Nuñez, Patricia Carvajal, Sergio Aguilera, María-José Barrera, Soledad Matus, Alicia Couto, Malena Landoni, Gaelle Boncompain, Sergio González, Claudio Molina, Karina Pino, Sebastián Indo, Lourdes Figueroa, María-Julieta González, Isabel Castro

Dynamic Transition of Regulatory T Cells to Cytotoxic Phenotype Amid Systemic Inflammation in Graves' Ophthalmopathy

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Abstract

Graves' disease (GD) is an autoimmune condition that can progress to Graves' Ophthalmopathy (GO), leading to irreversible damage to orbital tissues and potential blindness. The pathogenic mechanism is not fully understood. In this study, we conducted single-cell multi-omics analyses on healthy individuals, GD patients without GO, newly diagnosed GO patients, and treated GO patients. Our findings revealed gradual systemic inflammation during GO progression, marked by overactivation of cytotoxic effector T cell subsets, and expansion of specific T cell receptor clones. Importantly, we observed a decline in the immunosuppressive function of activated regulatory T cells (aTreg) accompanied by a cytotoxic phenotypic transition. In vitro experiments revealed that dysfunction and transition of GO-autoreactive Treg were regulated by the yinyang1 (YY1) upon secondary stimulation of thyroid stimulating hormone receptor (TSHR) under inflammatory conditions. Furthermore, adoptive transfer experiments of GO mouse model confirmed infiltration of these cytotoxic Treg into the orbital lesion tissues. Notably, these cells were found to upregulate inflammation and promote pathogenic fibrosis of orbital fibroblasts (OFs). Our results revealed the dynamic changes in immune landscape during GO progression and provided novel insights into the instability and phenotypic transition of Treg, offering potential targets for therapeutic intervention and prevention of autoimmune diseases.

Authors

Zhong Liu, Shurui Ke, Zhuoxing Shi, Ming Zhou, Li Sun, Qihang Sun, Bing Xiao, Dongliang Wang, Yanjing Huang, Jinshan Lin, Huishi Wang, Qikai Zhang, Caineng Pan, Xuanwei Liang, Rongxin Chen, Zhen Mao, Xianchai Lin

BAFF promotes follicular helper T cell development and germinal center formation through BR3 signal

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Abstract

T follicular helper (Tfh) cells represent an important subset of CD4+ T cells that is crucial to the maturation and differentiation of B cells and the production of high-affinity antibodies. Since BAFF, a vital B cell survival factor, is also crucial to B cell maturation and differentiation, we assessed the effects of BAFF on Tfh cell development and function. We demonstrate that deficiency of BAFF, but not of APRIL, markedly inhibits Tfh cell development, germinal center (GC) formation, and antigen-specific antibody production. The promoting effect of BAFF on Tfh cell development is dependent on expression of BR3 on T cells, and its promoting effect on GC formation is dependent on expression of BR3 on both T cells and B cells. BAFF directly promotes expression of the Tfh cell-characteristic genes via NF-κB signaling. This effect does need BR3 expression. Thus, BAFF not only has direct effects on B cells, but it also has direct effects on Tfh cell differentiation via engagement of BR3 which collectively promote GC formation and production of high-affinity antibodies. This dual effect of BAFF on B cells and Tfh cells may help explain the clinical utility of BAFF antagonists in the management of certain autoimmune diseases.

Authors

Ye Chen, Maogen Chen, Yu Liu, Qiang Li, Youqiu Xue, Liu Liu, Rongzhen Liang, Yiding Xiong, Jun Zhao, Jingrong Chen, Weidong Lin, Julie Wang, YunFeng Pan, William Stohl, Song Guo Zheng

A positive cytokine/chemokine feedback loop establishes plasmacytoid dendritic cell-driven autoimmune pancreatitis in IgG4-related disease

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Abstract

The pathogenesis of the murine model of autoimmune pancreatitis associated with IgG4-related disease (AIP/IgG4-RD) induced by administration of polyinosinic-polycytidylic acid, is incompletely understood. While it is known that murine and human AIP/IgG4-RD is driven by plasmacytoid dendritic cells (pDCs) producing IFN-α, the origin of these cells and their relation to effector T cells is not known. Here we show that murine AIP was initiated by TLR3-bearing conventional DCs in the uninflamed pancreas whose activation by TLR3 ligand (polyinosinic-polycytidylic acid) caused IFN-α, CXCL9, and CXCL10 secretion. This, in turn, induced pancreatic recruitment of CXCR3+ T cells and these T cells, via their secretion of CCL25, facilitated migration of pDCs bearing CCR9 into the pancreas. This established a feedback loop anchored by the now dominant pDC production of IFN-α and the continued CXCR3+ T cell facilitation of pDC migration. Remarkably, the interaction between CXCR3+ T cells and pDCs also existed at the functional levels since this interaction enhanced the production of CCL25 and IFN-α by CXCR3+ T cells and pDCs, respectively. Evidence presented here that a similar disease mechanism was present in human AIP/IgG4-RD creates new avenues of disease treatment.

Authors

Akane Hara, Tomohiro Watanabe, Kosuke Minaga, Tomoe Yoshikawa, Masayuki Kurimoto, Ikue Sekai, Yasuhiro Masuta, Ryutaro Takada, Yasuo Otsuka, Ken Kamata, Shiki Takamura, Masatoshi Kudo, Warren Strober

Dopamine receptor autoantibody signaling in infectious sequelae differentiates movement versus neuropsychiatric disorders

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Abstract

Despite growing recognition, neuropsychiatric diseases associated with infections are a major unsolved problem worldwide. Group A streptococcal (GAS) infections can cause autoimmune sequelae characterized by movement disorders, such as Sydenham chorea (SC), and neuropsychiatric disorders. The molecular mechanisms underlying these diseases are not fully understood. Our previous work demonstrates that autoantibodies (AAbs) can target dopaminergic neurons and increase dopamine receptor D2 (D2R) signaling. However, AAb influence on dopamine receptor D1 (D1R) activity is underexplored. We found evidence that suggests GAS-induced cross-reactive AAbs promote autoimmune encephalitis of the basal ganglia (BGE), a region of high dopamine receptor density. Here, we report a new mechanism whereby neuropsychiatric syndromes are distinguished from movement disorders by differences in D1R and D2R AAb titers, signaling, receiver operating characteristic (ROC) curves, and immunoreactivity with D1R and D2R autoreactive epitopes. D1R AAb signaling was observed through patient serum AAbs and novel patient-derived mAbs, which induced both D1R G protein- and -arrestin transduced signals. Furthermore, patient AAbs and mAbs enhanced D1R signaling mechanisms mediated by the neurotransmitter dopamine. Our findings suggest that AAb-mediated D1R signaling may contribute to the pathogenesis of neuropsychiatric sequelae and inform new options for diagnosis and treatment of GAS sequelae and related disorders.

Authors

Chandra M. Menendez, Jonathan Zuccolo, Susan E. Swedo, Sean Reim, Brian Richmand, Hilla Ben-Pazi, Abraham Kovoor, Madeleine W. Cunningham

Analysis of CNS autoimmunity in genetically diverse mice reveals unique phenotypes and mechanisms

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Abstract

Multiple sclerosis (MS) is a complex disease with significant heterogeneity in disease course and progression. Genetic studies have identified numerous loci associated with MS risk, but the genetic basis of disease progression remains elusive. To address this, we leveraged the Collaborative Cross (CC), a genetically diverse mouse strain panel, and experimental autoimmune encephalomyelitis (EAE). The thirty-two CC strains studied captured a wide spectrum of EAE severity, trajectory, and presentation, including severe-progressive, monophasic, relapsing remitting, and axial rotary (AR)-EAE, accompanied by distinct immunopathology. Sex differences in EAE severity were observed in six strains. Quantitative trait locus analysis revealed distinct genetic linkage patterns for different EAE phenotypes, including EAE severity and incidence of AR-EAE. Machine learning-based approaches prioritized candidate genes for loci underlying EAE severity (Abcc4 and Gpc6) and AR-EAE (Yap1 and Dync2h1). This work expands the EAE phenotypic repertoire and identifies novel loci controlling unique EAE phenotypes, supporting the hypothesis that heterogeneity in MS disease course is driven by genetic variation.

Authors

Emily A. Nelson, Anna L. Tyler, Taylor Lakusta-Wong, Karolyn G. Lahue, Katherine C. Hankes, Cory Teuscher, Rachel M. Lynch, Martin T. Ferris, J. Matthew Mahoney, Dimitry N. Krementsov

Bank1 modulates the differentiation and molecular profile of key B cell populations in autoimmunity

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Abstract

This study aimed at defining the role of the B-cell adaptor protein BANK1 in the appearance of age-associated B cells (ABCs) in two SLE mouse models (TLR7.tg6 and Imiquimod-induced mice), crossed with Bank1-/- mice. The absence of Bank1 led to a significant reduction in ABC levels, also affecting other B cell populations. To gain deeper insights into their differentiation pathway and the impact of Bank1 on B cell populations, a single-cell transcriptome assay was performed. In the TLR7.tg6 model, we identified 10 clusters within B cells, including an ABC-specific cluster which was decreased in Bank1-deficient mice. In its absence, ABCs exhibited an anti-inflammatory gene expression profile, while being pro-inflammatory in Bank1-sufficient lupus mice. Trajectory analyses revealed that ABCs originated from marginal zone and memory-like B cells, ultimately acquiring transcriptional characteristics associated with atypical memory cells and long-lived plasma cells. Also, Bank1 deficiency normalized the presence of naïve B cells, which were nearly absent in lupus mice. Interestingly, Bank1 deficiency significantly reduced a distinct cluster containing IFN-responsive genes. These findings underscore the critical role of Bank1 in ABC development, impacting early B cell stages towards ABC differentiation, and the presence of IFN-stimulated gene-containing B cells, both populations determinant for autoimmunity.

Authors

Gonzalo Gómez Hernández, Daniel Toro-Domínguez, Georgina Galicia, María Morell, Marta E. Alarcón-Riquelme